Zero Emissions Power Generation Boiler

ABSTRACT

This is a zero emissions power generation boiler that can be used to drive a wide range of steam turbines, from 20 MW up to 1200 MW, creating dry steam pressure ranging from 1000 psi up to 4500 psi. It creates steam by burning liquid hydrogen with liquid oxygen, completely eliminating the emission of greenhouse gases, lethal poisons, and every form of pollutant. It employs high-pressure cryogenic fuel pumps, a water cooling system, an electronic sparking system, a double-wall cylindrical boiler with a hemispherical top, and a control system that employs electronic sensors, actuators, signal conditions, microprocessors, digital interfaces, and mechanical back-up systems. It can be used in new power plants or as a replacement for current boilers in existing power plants. It has the option of working as part of a combined cycle system and can employ steam reheat systems.

CROSS-REFERENCE TO RELATED APPLICATIONS

The inventor, James H. Carrow, has two other patent applications pendingat this time, U.S. Utility patent application Ser. No. 17/027,068 andU.S. Utility patent application Ser. No. 17/093,042. Neither oneconflicts with this application in any way; they are for totallydifferent designs.

STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

THE NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC OR ASA TEXT FILE VIA THE OFFICE ELECTRONIC FILING SYSTEM (EFS-WEB)

Not applicable.

STATEMENT REGARDING PRIOR DISCLOSURES BY THE INVENTOR OR A JOINTINVENTOR

Not applicable.

BACKGROUND OF THE INVENTION (1) Field of the Invention

This patent application is for a design that is in the field of lowemissions (zero harmful emissions) power generation, specifically for aboiler system that can be used in existing or new power plants to supplyhigh-pressure steam to steam turbines, which in turn produce shaft powerthat drives electrical generators that send the power out to powergeneration utility customers. This design can produce enough steam todrive a wide range of boiler-driven steam turbines, up to 1200 MW inoutput, while eliminating all of the harmful emissions associated withcurrent coal-burning, natural gas-burning, refuse-burning, andbiomass-burning boiler systems, including greenhouse gases like carbondioxide, methane, and nitrous oxide, lethal poisons like carbonmonoxide, small particulate matter, large particulate matter, volatileorganic compounds, hydrogen sulfide, radioactive waste, and carbonblack, and known pollutants like sulfur dioxide, nitrogen dioxide, andunburned hydrocarbon molecules and fragments. The only emissions will besteam, water vapor, and unburned atmospheric gases like oxygen andhydrogen, all harmless to humans, plants, animal life, and the world'sclimate. Power generation companies today have to spend huge amounts ofcash designing and building complex emissions control equipment fortheir boilers. This design can eliminate 100% of that emissions controlequipment which, over the past decades, has often cost more to buildthan the entire rest of the plant combined.

Specifically this design uses the combustion of liquid hydrogen andliquid oxygen to produce steam in the boiler. There are no such designson the market today, but the availability of those two fuels isincreasing dramatically every year, and their price is now within reachof utility companies all over the world, which was not the case just oneor two years ago.

(2) Description of Related Art Including Information Disclosed Under 37CFR 1.97 and 37 CFR 1.98

The USPTO search of prior related patents requested by the inventor inthis application procedure produced two patents and two patentapplications. The inventor will discuss each of these in chronologicalorder.

The first two are U.S. Pat. No. 5,761,896-A, by Thomas Dowdy, from June,1998, and U.S. Pat. No. 5,953,900-A, by Roger Bannister, from September,1999. As more than twenty years has elapsed since these two patents wereapproved, they are no longer in force.

Both are patents for power plant combustion turbines, rather than boilersystems. The inventors, both of whom worked for the same company,Westinghouse, were trying to design combustion turbines that burn avariety of fuels, including air, gaseous oxygen, gaseous hydrogen,liquid oxygen, and liquid hydrogen. Their designs sometimes includedcompressors, sometimes included combustors, and were often cooled withwater. They were apparently attempting to patent a whole range ofdifferent designs. Most of the descriptions pertain to gaseous fuels,rather that cryogenic fuels, and the patents contain no descriptionswhatsoever of cryogenic tanks, lines, valves, pumps, sensors, actuators,or burners. In fact, each of them only uses a few short words andphrases to describe cryogenic fuels, their basic approach is to describegaseous fuel usage. Bannister's, for instance, is a series of threeturbines, a high-pressure turbine, an intermediate pressure turbine, anda low pressure turbine. The specifications quoted for the steam in thecombustor for the high pressure turbine are 250 bar (3675 psi) and 1600C. degrees (2912 degrees F.). It is not clear exactly what materials heplanned to use, what kind of pumps he planned on using to inject fuel atthat pressure, or what kind of injection system he had planned. Whateverthey were, they were probably not something that could be built andoperated today. No models of these designs exist at this time, perhapsfor that reason.

The third source cited is patent application US-20140283499-A1, byJean-Michel Sannino, dated September, 2014. This one, by an employee ofSNECMA, is for submerged electrical booster pumps in cryogenic fueltanks in rocket designs, particularly hydrogen tanks. This inventor isalso attempting to patent multiple designs with one application; thereare at least a dozen variations in the copy and drawings, and thedesigns include several variations on turbopumps, in addition to theelectrical pumps. It appears to be potentially workable if the inventorcan find pumps that work submerged in cryogenic hydrogen at about 15Kelvin or so (−432.67 degrees F.). A pump like that would require veryspecialized lubricants, materials, parts, wiring, and electricalconnections, no question about it. However, it is a rocket design,intended for use in extremely short bursts with a limited power range,often a few minutes or less, and as such is probably not suitable forpower generation use.

The fourth source cited is patent application US-20200072458-A1 byJoshua Partheepan, dated March, 2020. This one is a long applicationthat describes what could be over a thousand potential variations in asteam-production scheme that may be patterned after the kind ofpre-mixed gaseous hydrogen and gaseous oxygen found in oxyhydrogenwelding equipment. This is a quote from the application

-   “[0008] These processes are categorized as either “premixed” or    “non-premixed (post-mixed). Premixed H2-O2 is used in small-scale    applications such as limelight, oxyhydrogen blowpipes, and    oxyhydrogen torches for cutting and welding. Non-premixed H2-O2 is    used in combustion chambers, steam generators, internal-combustion    engines, rocket engines, and other industrial and environmental    applications . . . [0011] . . . Hydrogen has several unique    characteristics related to combustion: wide range of flammability,    low ignition energy, small quenching distance, high flame speed and    high diffusivity, all of which makes premixed combustion too risky    due to the danger of flashbacks and explosions.”

Thus his “pre-mixed” design is totally different from the zero emissionsboiler design described in this application, which is, to use his ownterm, a “post-mixed” design. He hits the nail on the head with thoselines. It does not appear as though he can produce significant steampressure with his pre-mixed design and also avoid pre-combustion andexplosions. This is another quote from his application:

-   “[0123] In one embodiment, said steam generator system 100 can work    along with a steam engine, steam-turbine, gas-turbine, or electric    hybrid engine. It can completely replace gasoline, diesel, oil or    gas engines in trucks, trains, submarines, ships, tanks etc.”

It is not quite clear what he is referring to, possibly old-style steamengines or possibly steam turbines in trucks, tanks, trains, etc.

Whatever it is, it does not appear to be a workable design for producingsteam for modern steam turbines in power plants. He does not give onesingle temperature, pressure, or flow rate specification in the entireapplication, leaving us to guess at all of that. The current guess isthat the maximum pressure he can achieve with any of the thousand or sovariations in his designs, including eleven different fuel storagemethods, would be around 50-100 psi, if that, possibly enough for asmall turbine but nowhere near enough for power plant steam turbinesthat run at 1000-5000 psi or so.

BRIEF SUMMARY OF THE INVENTION

This is a design for a power plant steam boiler that runs on thecombustion of liquid hydrogen and liquid oxygen. The combustion takesplace in a large unit equipped with burners, a sparking system, a watercooling system, and a steam header that transfers pressurized steam fromthe boiler to the steam turbine and generator system. The two cryogenicfuels are sent to the boiler at variable pressure (up to 6000 psi) bycryogenic fuel pumps. The cooling water is pumped in just under boilingtemperature (around 205-210 F) at even higher pressures (5000-20,000psi), after being heated by a heat exchanger and a boiler pre-heatcycle. The boiler is designed to produce steam at around 1000-1200 F atpressures of around 1000-4500 psi, at flow rates of up to 10 millionpounds of steam per hour, or higher if necessary. The boiler andcryogenic tanks, pumps, valves, and lines are designed to work well atcryogenic temperatures without failure. The system operates off of largeliquid hydrogen, liquid oxygen, and water holding tanks. The entiresystem is equipped with pressure relief valves, check valves, blowbacksuppression valves, temperature sensors, pressure sensors, flow ratesensors, strain gauges, purging equipment, boil-off re-liquefactionequipment, fuel tank cooling equipment, booster pumps, and equipmentthat can relay actuator and sensor information and controls to a centralpower plant control room. It is designed to correct itself with aminimum of manual control.

This boiler design can also be outfitted with modern re-heat and doublere-heat systems, as required by the customer. It can be sized and builtto run everything from small 20 MW steam turbines up to large 1200 MWsteam turbines. It can be designed for brand-new power plants ordesigned as a retrofit installation for existing power plants, as areplacement for fossil fuel and renewable boiler systems. It can be runas a stand-alone design or as part of a combined cycle design where theexhaust from a combustion turbine is used as part of the waterpre-heating system. This design completely eliminates the emission ofharmful pollutants, poisons, and greenhouse gases, and in doing so alsoeliminates the need for large and extremely expensive emissions controlsystems.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

There are eight drawings in this submission, two perspectives, onecutaway perspective section, one plan, and four elevations.

FIG. 1: Front Perspective

This is a perspective rendering with a view from the upper right rear ofthe project. It shows the general layout of the boiler, the steamturbine and generator, the water pumps, and the cryogenic fuel pumps,plus the upper part of the water preheat system. The drawing does notshow power plant roofs and walls, the fuel holding tanks, the waterholding tank, the water cooling ponds, the turbine steam outlets, thecondenser, or the stack as these are not a part of the currentapplication. The steam turbine and generator are shown because theconnections and reheat system are a part of this application. Theturbine shown is based on a Siemens steam turbine design, and its designis not a part of this application.

FIG. 2: Rear Perspective

This is a perspective rendering with a view from the upper left front ofthe project, showing the back end of the generator, turbine, reheatsystem, steam header, and boiler. It should be noted that the waterpumps shown in these views are a reciprocating design based on pumpssold by GD Energy Products, their Thunder 5,000 HP Quintuplex model, andtheir design is not a part of this application.

FIG. 3: Perspective Cutaway Section

This is a cutaway perspective section with a view from the upper rightrear side of the project. The outer casing of the boiler is cut awayshowing the double shell with a thinner outer shell and thicker innershell, air-cooled from the outside. It shows a preliminary design forthe upper part of the water pre-heat system (the lower part, not shown,is a customer option, either a combined cycle system or a stand-aloneheat exchanger system). Inside the boiler walls are the water coolingsystem (outer rows of inlets) and the sparking and burner system (innerrows of electrical units and fuel injectors).

FIG. 4: Plan

The plan view is a bird's eye view of the project, showing the generallayout of the boiler, pumps, and steam turbine. The inner ring of pumpsare alternating high pressure liquid hydrogen and liquid oxygen pumps ofa multi-stage design powered by electric motors. These will have to be acustom design for this project.

FIG. 5: Right Elevation

This elevation view shows the project from the right side. The boiler,steam header, and steam turbine can be clearly seen.

FIG. 6: Rear Elevation

This elevation view shows the project from the rear. The upper part ofthe water preheat system can be seen in front of the boiler.

FIG. 7: Left Elevation

This elevation view shows the project from the left.

FIG. 8: Front Elevation

This elevation view shows the project from the front.

DETAILED DESCRIPTION OF THE INVENTION

This zero [harmful] emissions power generation boiler is being designedas a potential replacement for power plant boilers all over the worldthat drive steam turbines by boiling water using nuclear fission or thecombustion of coal, natural gas, fuel oil, biomass, and garbage. Theidea is to replace all of the harmful emissions and by-products of thosesystems, including greenhouse gases like carbon dioxide, methane, andnitrous oxide; poisons like radioactive waste, small particulate matter,carbon monoxide, hydrogen sulfide, large particulate matter, volatileorganic compounds, and carbon black; and known pollutants like nitrogendioxide, sulfur dioxide, unburned and partially burned hydrocarbons,coal ash, spent nuclear fuel rods, and unburned waste with emissionsthat are nothing but water, water vapor, steam, oxygen, and hydrogen,the latter two pure atmospheric gases. The idea is to take the currentdeadly mix, responsible for around 10-50% of the world's air pollutionand greenhouse gas emissions today, depending on the nation involved, amix which plays a part in millions of fatalities worldwide every year,and replace it with a system whose emissions are completely harmless tohumans, plants, and animals.

This can be accomplished by this design in a manner that does notdecrease, in any way, the potential power or efficiency of modern powerplants. In doing so it can totally eliminate the massively expensive andspace-consuming scrubbers and emissions control equipment that today cancost more than the entire thermal energy plant they are designed around,and replace immensely expensive and often quite dangerous nuclear powerplants near highly populated areas.

Today the world is witnessing a quiet revolution in energy production,in which green hydrogen and its companion product, oxygen, are startingto replace traditional fossil fuels, biomass, and garbage ascombustibles. The price of those two fuels is now beginning to come downto a level that can make their use competitive with their rivals. Fuelcosts are often fifty percent of the running costs of a typical powerplant. The day is dawning, as natural gas and fuel oil prices skyrocketthis year, as highly-polluting brown coal [lignite] is the only form ofcoal utility companies can afford to burn any more, as biomass andgarbage are starting to be recognized for the dangerous polluters thatthey really are in practice; and as nuclear plants continue to get moreand more expensive, when plants that burn hydrogen and oxygen to producepower will become competitive, not just in terms of initial constructioncosts, but also in terms of yearly miming costs and longevity, withtheir dirty and deadly emissions rivals in that market.

This zero emissions boiler is a different kind of power plant boilersystem. First off, it burns two cryogenic fuels, liquid hydrogen andliquid oxygen, pumped to burners at its base by high-pressuremulti-stage cryogenic fuel pumps at high pressure, to produce the steam.The fuels are lit by high-powered sparking systems between each pair offuel injectors which can automatically deploy repeatedly if for somereason the flame from those injectors dies out. The fuels themselves areatomized by the injector heads to make mixing and ignition easier, butat the massive volumes required by modern power plants.

This process produces both high temperatures and high pressures. Liquidhydrogen and liquid oxygen burn with a fairly hot flame and can createas much steam pressure as the boiler walls and fuel injection pressurewill allow. Modern steam turbines operate over a range of pressures,from around 1000 psi all the way up to around 4500 psi. This boilerdesign can work at any pressure in that range and can go all the way upto the maximum if the boiler walls and fuel pumps are built to handlethe high tensile stress and pressure.

While the burners are in the middle of the boiler, at the bottom, andare placed some distance from the outside wall, with continuous use theradiant and convective heat from the flame will eventually create issuesin that wall. There are, at this time, two different methods of coolingthe boiler to prevent issues. The first, and more expensive method, isto increase the percentage of oxygen in the mix, which will cool theflame and shorten its length. The second one, envisioned as the everydaymethod in this instance, is pumping water, pre-heated to about 205-210degrees F., at extremely high pressure into the boiler through a fairlywide ring of nozzles set in between the flame and the wall. The water,aimed at the walls and at the top of the boiler, will keep those wallscooled down to a temperature that will obviate thermal expansion andcreep issues, and will also cool down the steam to a planned 1000-1150degrees Fahrenheit, the so-called “dry steam” employed by modern steamturbines to lower corrosion and wear and tear on their blades androtors. The cooling water, turning to steam itself at that temperature,will itself create even more steam pressure in the boiler.

Once the desired steam pressure and temperature have been achieved, thevalve to the steam header at the top of the boiler will open up andsupply steam to the turbine, causing its rotors and shaft to spin andturn the generator rotor, creating electrical current for the powerplant. The design is planned to be practically self-regulating, withpump speeds continually adjusted by the plant control center to achievethe best possible steam temperature and pressure and optimal turbinerotor speeds.

This boiler design can accommodate either no steam re-heat, single steamre-heat, or double steam re-heat systems, depending on the turbine typesused in the plant and the desires of the customer. The drawingssubmitted show a single steam re-heat system. It can work with a widerange of steam turbines, from about 20 megawatts (a small boiler) allthe way up to about 1200 megawatts (the size of boiler shown in thesubmitted drawings). It can produce up to and above 10 million pounds ofsteam per hour. It can work as a single unit or as part of a largemulti-unit power plant. It can be run as a stand-alone unit, powered bya dedicated heat exchanger in the water pre-heat system, or as part of acombined cycle plant, in which the water pre-heat system is powered bythe hot exhaust from a combustion turbine sent through a heat exchangersystem. The pre-heat system can also use passes through the boiler inpipes, in part, as shown in the submitted drawings, powered by waterpumps. This system is also designed to be practically self-regulatingand controlled by the power plant control room.

The water used to supply the cooling system is produced in a condenser(not shown in the drawings) at the far end of the generator and suppliescooling ponds (not shown in the drawings) adjacent to the boiler. Theseare not a part of this patent application and their design is adiscretionary one for the customers.

The cryogenic fuel tanks include the main tanks (not shown in thedrawings) and holding tanks (not shown in the drawings), hopefullyequipped with pressure relief valves, cryogenic valves, booster pumps,cooling systems, boil-off re-liquefaction systems, phase controlsystems, and purging systems, but the size and style of these tanks is adiscretionary one, based on customer design, the size of the turbinesand plants, cost, fuel supplies, and other considerations, and they arenot a part of this patent application.

The high-pressure water pumps shown in the drawings are based on areciprocating five-cylinder design of GD Energy Products capable ofproducing up to 20,000 psi, and only their layout, not their design, isa part of this patent application.

The high-pressure cryogenic fuel pumps shown in the drawings will haveto be a custom multi-stage design built to handle cryogenic fuels andthe particular issues involved with pumping liquid hydrogen at thesepressures. However, many successful high-pressure liquid oxygen andliquid hydrogen pumps have been designed in the past and there arecompanies that specialize in jobs like that. Their actual design,including lubrication design, stage design, and electrical motor design,are a bit below the scale of this patent submission and await furtherrefinement, but their arrangement, shown in the drawings, is a part ofthis patent application.

The design of the high pressure fuel injectors and their sparkingsystems are also a bit below the scale of this patent submission, buttheir arrangement, shown in the cutaway perspective section drawing, isdefinitely a part of this patent application. The same goes for theouter rings of water nozzles shown in that drawing, their arrangement isdefinitely part of this patent application, but their design is a bitbelow its present scale and await further refinement.

The boiler pass-through piping of the water pre-heat and re-heat systemsis shown in the drawings, but these are optional features in this designand up to the customers. The pre-heat pass-through pipes can be locatedat either the top or the bottom of the boiler, depending upon customerpreference.

The cylindrical boiler wall and hemispherical roof design shown in thedrawings are definitely a part of this patent application. This is adouble-wall boiler, with the inner wall designed to handle all of thepressure inside the boiler and the outer wall with a thinner section,perforated for air cooling, designed to reinforce the inner wall andclose up the gaps to prevent pressure leaks. The walls are designed insections, joined by nuts, bolts, gaskets, O-rings, and sealants. Theinner wall sections have large flanges for use in those connections andfor reinforcement. The material of the inner wall will have to be ableto handle a very wide range of temperatures and pressures, rust issues,oxidation issues, and hydrogen embrittlement issues and will probablyend up being a high-strength nickel alloy of some kind. The outer wallmay be a high-strength nickel or stainless steel alloy. These walls willtechnically be designed for a life of around 40 years or so withoutfailure and so creep and repeated expansion and contraction will becritical issues in their design. The boiler may have to be periodicallyshut down for inspection, maintenance, and cleaning.

The steam header shown is a relatively standard design in modern powerplants. There are no foreseeable variations in this design. Theconnections to the steam turbine vary with turbine design and aretherefore not a part of this patent application.

This zero emissions boiler is designed to work in conjunction with amodern power plant control room and its display, monitoring, andactuating systems. These control rooms are designed by companies thatspecialize in that trade and the control room layout is not a part ofthis patent application, The sensors and actuators in this boiler arerun through dedicated signal conditions, microprocessors, and digitalinterfaces that allow them to function in coordination with the plantcontrol room.

There are many aspects of this boiler design that are controlledautomatically, and many that may be subject to manual control at times.The temperature and pressure in the main fuel tanks and fuel holdingtanks are designed as an automatic process, with feedback loops from thesensors controlling the cooling and re-liquefaction systems in thosetanks. This is particularly important for the liquid hydrogen, which hasto be contained within a very specific temperature and pressure range,and in a very specific phase, in order to lessen multi-phase flow,slush, cavitation, and dangerous vaporization in the lines and pumps.This issue becomes less important at higher pressures after it reachesthe main fuel pumps, however. In addition, this system will be augmentedby manual control overrides and mechanical pressure relief valves.

The water pre-heat system will also be controlled automatically, withtemperature and pressure sensors working in feedback loops inconjunction with the heat exchanger and the water pumps, and will alsobe equipped with manual overrides where possible. The feedback loopscontrolling the pumps will also include strain gauges placed in theboiler walls. The two systems, including the main fuel pumps and thewater pumps, will also have a feedback system that includes boilertemperature and pressure gauges and data from the turbine and generatorrelated to their speed and power output. The fuel sparking system willalso be automatic, adjusted by temperature, pressure, and flow sensorsin the fuel lines and burners. The system will also be equipped withmanual overrides and sensor, actuator, valve, and pump failuremonitoring and protection.

So that is the sense in which this is being designed as an automaticsystem. Today sophisticated digital control systems can make adjustmentsin actuators hundreds of times per minute, and actually per second insome cases. They are just a lot faster and more accurate than humanreactions, as a rule, and thus can save utility companies a lot of moneyand prevent excessive down time. However, they do fail occasionally,thus the need for manual overrides and some mechanical back-up andsafety features.

There are certain safety issues in this design, including excessivepressure and flow blockages in the tanks, pipes, valves, and pumps,excessive pressure and temperature in the boiler and turbine, andhydrogen and oxygen leakage, that have to be addressed by safetyfeatures like mechanical pressure relief valves, emergency shut-downs,and hydrogen and oxygen monitoring equipment, but these things have allbeen done before successfully.

1. First claim: This zero [harmful] emissions power plant boiler is aunique design that can produce enough steam to run turbines ranging from20 MW to 1200 MW, at pressures of 1000-4500 psi, by means of burningliquid hydrogen and liquid oxygen, completely eliminating the emissionof greenhouse gases, lethal poisons, and all known pollutants, in asystem comprising: cryogenic fuel tanks high-pressure cryogenic fuelpumps rings of centrally-located burners an electronic sparking system.2. Second claim: The boiler is a unique, double-walled cylindricaldesign with a hemispherical top capable of handling the high stressesinvolved, in which steam pressure is created in the central cavity,rather than in a system of piping along the sides, and is comprised of:an outer wall an inner wall a steam header at the top.
 3. Third claim:The boiler is cooled by a system of water pumps that send heated waterat high pressure to rings of nozzles located between the burners and thewalls, sending the water up into the central cavity where it becomessteam while cooling the walls and top of the boiler, in a systemcomprised of: cooling ponds a water holding tank a water pre-heat systemhigh-pressure reciprocating water pumps rings of nozzles at the base ofthe boiler
 4. Fourth claim: The boiler system is controlled by a largeseries of sensors, actuators, signal conditioners, microprocessors, anddigital interfaces that allow feedback loops run through the plantcontrol room to continually monitor and adjust cryogenic fueltemperature, pressure, and flow rate, cryogenic pump speed, electronicsparking system activation, water temperature and pressure, water pumpspeed, boiler steam temperature and pressure, boiler material stresses,and the temperature, pressure, and flow rate of the steam turbineintake, while being subject to manual and mechanical back-up systems,safety systems, and control overrides.